The present disclosure relates generally to a system for, and a method of, automatically avoiding signal interference between product proximity subsystems that emit signals through mutually facing presentation windows of different workstations.
Point-of-transaction workstations employing laser-based readers and/or imager-based readers have been used in many venues, such as supermarkets, department stores and other kinds of retail settings, as well as libraries and parcel deliveries and other kinds of public settings, as well as factories, warehouses and other kinds of industrial settings, for many years. Such workstations were often configured either as stand-mounted scanners each resting on a counter and having a presentation window; or as vertical slot scanners each resting on, or built into, the counter and having a generally vertically arranged, upright presentation window; or as flat-bed or horizontal slot scanners each resting on, or built into, the counter and having a generally horizontally arranged presentation window; or as bi-optical, dual window scanners each resting on, or built into, the counter and having both a generally horizontal presentation window supported by a generally horizontal platform and a generally vertically arranged, upright presentation window supported by a generally upright tower. Such workstations were often operated to electro-optically read a plurality of symbol targets, such as one-dimensional symbols, particularly Universal Product Code (UPC) bar code symbols, truncated symbols, stacked symbols, and two-dimensional symbols, as well as non-symbol targets, such as driver's licenses, receipts, signatures, etc., the targets being associated with, or borne by, objects or products to be processed by, e.g., purchased at, the workstations.
A user, such as an operator or a customer, slid or swiped a product associated with, or bearing, the target in a moving direction across and past a respective presentation window in a swipe mode, or momentarily presented, and steadily momentarily held, the target associated with, or borne by, the product to an approximate central region of the respective presentation window in a presentation mode. The products could be moved relative to the respective window in various directions, for example, from right-to-left, or left-to-right, and/or in-and-out, or out-and-in, and/or high-to-low, or low-to-high, or any combination of such directions, or could be positioned either in contact with, or held at a working distance away from, either window during such movement or presentation. The choice depended on the type of the workstation, or on the user's preference, or on the layout of the venue, or on the type of the product and target. Return light returning from the target in the laser-based reader and/or in the imager-based reader was detected to generate an electrical signal indicative of the target. The electrical signal was then processed, and, when the target was a symbol, was decoded, and read, thereby identifying the product.
Each workstation typically had an illuminator or illumination subsystem to illuminate the target with illumination light over an illumination field. Preferably, to reduce electrical power consumption, to prolong operational lifetime, and to reduce bright light annoyance to operators and customers, the illumination light was not generated at all times, but was generated in response to detection of return infrared (IR) light by an IR-based, product proximity or object sensor subsystem that included an IR emitter operative for emitting IR light into an IR emission field, and an IR sensor for sensing the return IR light within an IR detection field of view. A product entering the IR emission field reflected and/or scattered at least a portion of the emitted IR light incident on the product to the IR sensor. Detection of this return IR light by the IR sensor determined that the product had indeed entered the workstation, thereby triggering the illumination system and the reading of the target.
Although generally satisfactory for their intended purpose, one issue with such known presentation-type workstations involved the accidental generation of the illumination light when at least two presentation windows of different workstations faced each other. In some venue layouts, the IR sensor of a first workstation looking through a first presentation window might be so positioned so as to sense the IR light emitted by the IR emitter through a second presentation window of a second workstation. For example, this could occur when the first and second workstations were situated across an aisle such that their respective upright presentation windows generally faced each other. Put another way, the IR detection field of view of the IR sensor of the first workstation at least partially overlapped the IR emission field of the IR emitter of the second workstation. This accidental generation of the illumination light was not only very bothersome and annoying to operators and customers, but also wasted electrical power, and shortened the operational lifetime of the workstations.
To prevent such accidental generation of the illumination light, it was known to manually retrofit and individually configure each workstation. Thus, each workstation had to be manually reprogrammed in situ. This procedure had to be customized for each venue layout and required skilled personnel and non-negligible time to complete. If the procedure was done improperly, then false triggering of the illumination light continued.
Accordingly, there is a need to reduce such electrical power consumption, to prolong such operational lifetime, and to reduce such bright light annoyance to operators and customers by avoiding such accidental generation of the illumination light when the presentation windows of different workstations generally face each other, and to do so in an automatic manner that requires no skilled personnel or manual procedures of any kind.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and locations of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
The system and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.